In conjunction with twisting or cabling machines, it is known to maintain the centrifugal forces in the yarn balloon owing to the revolving yarn in balance by means of corresponding counter-forces in the inflowing outer yarn in order to ensure stable running conditions during operation of a cabling spindle. These counter-forces are formed, for example, from the sum of the frictional forces in the cabling spindle, on the storage disc, on the yarn running path and by a yarn brake. The yarn brake can generally be set so that the different running and force conditions can be taken into account depending on the yarn count, type of yarn or yarn preparation. In conjunction with twisting or cabling machines, hysteresis brakes are often used as yarn brakes, which, equipped with specially formed friction wheels, allow a finely metered and careful use of the braking forces.
Twisting or cabling machines of this type with mechanisms for setting the yarn tension of the inner yarn and/or the outer yarn are described in numerous patent applications, for example in German Patent Publications DE 41 913 A1, or DE 100 30 888 B4, or in European Patent Publication EP 1 167 597 B1, sometimes in great detail.
In the cabling spindles known from German Patent Publication DE 100 30 888 B4 or European Patent Publication EP 1 167 597 B1, a storage disc is, for example, dispensed with and, instead, the yarn tension is controlled substantially by a pot rotating with the cabling spindle, which pot substantially prevents the formation of a free yarn balloon except for a residual balloon. The known cabling spindles are also, in each case, equipped with mechanisms particular to the workstation to set the yarn tension of the outer yarn, which mechanisms may be different in configuration.
It is, for example, described in German Patent Publication DE 100 30 888 B4 that this mechanism is either configured as a yarn brake or as a mechanism, with which the outer yarn can not only be braked, but also actively conveyed. The yarn influencing mechanism known from European Patent Publication EP 1 167 597 B1 is preferably also configured as an active feed device.
The use of a co-rotating pot has, however, proven to be disadvantageous in the cabling devices known from German Patent Publication DE 100 30 888 B4 or European Patent Publication EP 1 167 597 B1, as the pot, on the one hand, is subject to not insignificant wear owing to the rotating outer yarn and, on the other hand, also has to be moved as a rotating mass by the spindle drive. In addition, the air friction of the pot causes additional losses, which have to be compensated by the spindle drive.
A cabling spindle is known from German Patent Publication DE 41 21 913 A1, in which the yarn tension of an inner yarn and an outer yarn is influenced by means of adjusting mechanisms in such a way that the yarns at the cabling point have the same yarn tension and the same yarn speed. The inner yarn is acted upon here by an inner yarn brake, the braking effect of which is controlled depending on the outer yarn/balloon yarn tension.
The outer yarn is introduced centrally into the cabling spindle, proceeding from the outer yarn brake, and leaves radially at a rotating storage disc, which is fastened below the twist plate at the cabling spindle. The outer yarn loops the storage disc here, at least partially, before the yarn is transferred via the outer edge of the twist plate into a free yarn balloon.
As the shape and the diameter of a free yarn balloon decisively co-determine the energy consumption at each cabling spindle, it has furthermore already been proposed, for example by German Patent Publication DE 10 2008 033 849 A1, to set the feed speed of the outer yarn by means of an active yarn feed device in such a way that no yarn storage is adjusted, but the yarn tension adopts a value, which minimizes the diameter of the free yarn balloon circling around the spindle depending on the geometry of the spindle. It was possible to achieve considerable energy savings with the embodiment of a cabling spindle known from German Patent Publication DE 10 2008 033 849 A1 during operation compared to the cabling spindles known until then.